Phosphoric and thiophosphoric phenol esters containing an azo group and methods of preparing same



wherein M represents an alkali metal.

United States Patent PHOSPHORIC AND THIOPHOSPHORIC PHENOL ESTERS CONTAINING AN AZO GROUP AND METHODS OF PREPARING SAME Giuseppe Losco and Cesare Augusto Peri, Milan, Italy,

assignors to Montecatini-Societa Generate per lIndustria Mineraria e Chimica, a corporation of Italy The present invention relates to a new class of compounds of the general formulas:

110 2"; R I no Ito i": R n) wherein R represents a low molecular weight alkyl, e.g. methyl or ethyl, X is oxygen or sulfur, R is a hydrogen atom or a halogen or a monovalent radical, e.g. N0 OCH OC H CH and to a process for obtaining them.

The radical R can be in the ortho-, metaor paraposition with respect to the nitrogen atom. In the group of azoxy derivatives (Formula II) the oxygen atom can be isomerically bound to either nitrogen atom.

We have found that compounds, defined by the aforementioned formulas, have antiparasitic properties and are very effective in control of the domestic fly, including strains resistant to the usual chlorinated insecticides.

These compounds show, generally, a very low toxicity towards warm blooded animals as indicated by experiments with rats, including oral and intravenous administration of definite amounts of these compounds.

Another outstanding characteristic is the remarkable stability of these materials and their persistence on the walls, which assures a long duration of the anti-parasitic action.

It is, therefore, one of the objects of the present invention to furnish new phosphoric and thiophosphoric esters containing an azo group.

It is a further object of the invention to furnish in these controlling the house fly.

2,947,663 Patented Aug. 2, 1960.

ICC

The reaction is carried out in a solvent for one or both reactants, at temperatures between 0 and 150 C.

In the alternative, instead of using an alkaline salt of the phenolic compound, the free phenolic compounds and a basic metal compound of sufiicient alkalinity to bind the hydrohalogenic acid set free during the reaction may be used (for example: sodium or potassium hydroxide, sodium or potassium carbonate, sodium methylate or ethylate).

The desired materials, obtained after removal of the reaction by-products, can be purified by crystallization from suitable organic solvents or by means of a high vacuum distillation. In some cases, chromatographic purification on alumina may be used.

We also found that thiophosphoric esters (X being sulfur) of this invention can be transformed into the corresponding phosphoric esters (X being oxygen) by means of suitable oxidants, such as hydrogen peroxide in an acetic medium.

The conversion of the azo group into an azoxy group can also be. carried out by reacting hydrogen peroxide with the phosphoric esters.

Thecompounds of the present invention can be used in many formulations. In general it is convenient to dilutethem with solid, liquid or semisolid vehicles (in the form of a paste) wetting agents, adhesives, dispersing agents, emulsifiers, etc. can be added thereto. Other substances having an insecticidal or, generally, antiparasitic action can also be added thereto.

The following examples are submitted to illustrate, but

in no way to limit, the present invention.

EXAMPLE 1 18.2 g. of the 0,0-diethylthiophosphoric acid chloride are added to a suspension of 25 g. of p-nitro-benzeneazophenol sodium salt in 150 cc. of acetone. The mixture is refluxed for 2 hours while vigorously stirring. Sodium chloride is removed by filtration and the acetone solution is concentrated. The residue, crystallized from methyl alcohol, yields 19 g. of a brick red material (M.P. 71-72 C.) consisting of p-nitrobenzene azophenol 0,0-diethylthiophosphoric ester.

Using the sodium salt ofbenzene azophenol and proceeding in the same manner, benzene azophenol 0,0-diethylthiophosphate is obtained, consisting of red crystals having a melting point of 53f C.

' It is a still further object of the invention to provide methods of preparing these compounds.

These and other objects and advantages of the present invention will appear more clearly from the hereinfollowing detailed description and the examples. i

The compounds of the present'invention are obtained .by reacting an halide of an 0,0-dia1kylphosphoric or thiophosphoric acid having a general formula pounds of the following types:

R (IV) (III) EXAMPLE 2 19.8 g. of benzene azophenol and 10 g. of finelypulverized potassium carbonate are added to cc. of acetone. The mixture is vigorously stirred and 17.5 g. of 0,0-diethylphosphoric acid chloride are introduced. After refluxing for 4 hours while stirring is continued, and cooling, the mixture is poured into water. The oil which separates thereupon is extracted with carbon tetrachloride and washed, first With an aqueous solution of 5% K CO and then with water. After evaporation of the solvent, 27 g. of an orange colored oil, which can be purified by vacuum distillation (residual pressure O.2-0.3 mm. Hg; oven temperature ZOO-230 C.) are obtained. The compound obtained is benzene-azophenoh 0,0-diethylphosphoric ester.

Proceeding in the same manner, the following products 4(4-chloro-benzene-azo)phenol 0,0-diethylphosphoric ester; crystals (from petroleum ether), M.P. 48-49 C., 4(4-ethoxy-benzene-azo)phenol 0,0-diethylphosphoric ester; crystals (from ligroine), M.P. 42.5-43" C., 4(4-nitrobenzene-azo)phenol 0,0-diethylphosphoric ester; crystals (from ligroine), M.P. 92-93 C.,

EXAMPLE 3 22.8 g. of 4(4'-rnethoxy-benzene-azo)phenol and 10g. of finely pulverized K are added to 150 cc. of acetone. The mixture is vigorously stirred and 188g of the 0,0-diethylthiophosphoric acid chloride are introduced.

The mixture is refluxed for 4 hours while stirring and, after cooling, poured into ground ice. The solid material which separates is washed with a K CO solution and then with water. 17 g. of 4(4'-methoxy-benzene-azo)- phenol 0,0-diethylthiophosphoric ester are obtained; crystals (from methanol), M.P. 41-42 C.

Proceeding in a similar manner, the following products have been prepared:

4(4'-chloro-benzene-azo)phenol 0,0-diethylthiophosphoric ester; crystals, M.P. 48 C.,

4(4 ethoxy benzene azo)phenol 0,0-diethylthiophosphoric ester; crystals (from methanol), M.P. 56-57 C.,

4(4-nitro-benzene-azo)phenol 0,0-diethylthiophosphoric ester; (see Example 1),

4(3'-nitro-benzene-azo)phenol 0,0-diethylthiophosphoric ester; crystals (from methanol), M.P. 50-5 1 C.,

4(2'-nitro-benzene-azo)phenol 0,0-diethylthiophosphoric ester; an oil which can be purified by chromato graphy on A1 0 4(2' chloro benzene azo) phenol'0,0 diethylthiophosphoric ester; an oil which can be purified by chromatography on A1 0 4(4-tolyl-azo)phenol 0,0-diethylthiophosphoric ester; an oil which can be-purified by chromatography on A1 0 4(2-methoxy-benzene-azo)phenol 0,0-diethylthiophosphoric ester; an oil which can be purified by chromatography on A1 0 4(u-napthyl-azo)phenol 0,0-diethylphosphoric ester; an oil which can be purified by chromatography on A1 0 EXAMPLE 4 4(4'-chloro-benzene-azo)phenol OgO-dimethylthiophosphoric ester; crystals (from methanol), M.P. 7778 C., 4(4'-methoxy-benzene-azo)phenol '0,0-dimethy1thiophosphoric ester; crystals (from methanol),'M'.P. 636'4 -C.

EXAMPLE 5 38 g. of a highmelting benzene-.azoxy-phenol isomer 2,947,6 3 r H I 4 (Angeli, Gazz. Ch. It. 46, II, 106), 18.5 g. of potassium carbonate and 31.5 g. of 0,0-diethylthiophosphoric acid chloride are added to 200 cciof acetone. The mixture is refluxed for 4 hours while vigorously stirring, and is then cooled to room temperature, by pouring the mixture into ground ice. The solid product obtained in this manner is crystallized from methanol. The high melting isomer of benzene-azoxy-phenol 0,0-diethylthiophosphotic ,ester is obtained, M.P. 35 5-37" C.

Using the low melting isomer of benzene-azoxy-phenol (loc. cit.) and operating in a similar manner, the correresponding 0,0-diethy1thiophosphoric ester is obtained consisting of a light-yellow oil which, when purlfied by chromatography on A1 0 produces a crystalline material melting at 27-28" C.

EXAMPLE 6 12.4 g. of- 4(4-chloro-benzene-azoxy)phenol, 5 g; of K CO and 8 g. of 0,0-dimethylthiophosphoric acidchloride are added to 80 cc. of acetone. The mixture is refluxed for 4 hours while vigorously stirring, and is then cooled and poured into water. The separated solid is filtered off, washed with a 5% K 00 solution and then with water.

17.3 g. of a solidmaterial which, when crystallized from methanol, melts at 72 C., are obtained. It consists of 4(4 chloro-benzene-azoxy)phenol 0,0-dimethylthiophosphoric ester.

Proceeding in a similar manner, the following products have been prepared:

Benzene-azoxy-phenol 0,0-dimethylthiophosphoric .ester;

crystals (from methanol, M.P. 44-45 C.,

4(4-chloro-benzene-azoxy)phenol 0,0-dimethylthiophosphoric ester; crystals (from methanol), M.P. 49-50 C.,

4(4'-nitro-benzene-azoxy)phenol 0,0-dimethylthiophosphoric ester; crystals (from methanol), M.P. 7374 C.

EXAMPLE 7 the 4(4-chloro-benzene-azoxy) phenol 0,0-diethylphosphoricester.

Proceeding in a similar manner, the following products have been prepared:

Benzene-azoxy-phenol 0,0-diethylphosphoric ester; :an'

oil which can be purified by high vacuum distillation.

'4(4'-nitro-benzene-azoxy)phenol 0,0 diethylphosphoric ester; crystals (from ligroine), M.P. -91 C. 7

EXAMPLE .8

0,0-diethylphosphoric ester, identical with the material mentioned in Example 7, are obtained.

EXAMPLE? 39.5 g. of 4'(4'nitro-benzeneazo)phenol 0,0-diethyl-' thiophosphoric ester (Examples '1 and 3) are dissolved in 200 cc. of glacial acetic acid and carefully treated at C. with 75 cc. of 30% hydrogen peroxide. The mixture is heated ior :10 hours-on a'boilingwwat'er'rbath and treated as shown in Example 8. 27 g. of a crud product, substantially, consisting of 4(4'-nitro-benzene azoxy)phenol 0,0-diethylphosphon'c ester, are obtained.

Evaluation of the biological activity tests of products 5 named in the preceding examples Generally, the herein claimed products are highly efiicient insecticidal compounds and are useful in the control of parasites, particularly the fly.

The following examples illustrate these characteristics.

EXAMPLE 10 Upon topic application, with a rnicrosyringe, of an acetone solution of the test products on 5-day old domestic flies, the following percent average mortalities have been obtained after hours:

20 A. benzene-azo-phenol 0,0-diethylthiophosphoric ester 100 100 18 B. henzene-azoxy-phenoL0,0-diethylthiophosphoric ester (low melting isomer) 100 100 48 O. benzene-azoxy-phenoL0,0-diethylthiophosphoric ester (high melting isomer) 100 100 79 l D. 4(4'-ohloro-benzene-azo) phenol phosphoric ester 100 100 75 E. 4.(4'-nitro-benzene-azo)phenol O-O-diethylthiophosphoric ester 100 100 98 F. 4(3-nitro-benzene-azo)phenol 0,0-diethylthiophosphoric ester 100 100 100 G. 4(2-nitro-benzene-azo)pheuol O-O,diethy1thiophosphoric ester .4 100 100 2 H. benzene-azoxy-phcnol 0,0-diethylphosphoric 3O ester 100 100 65 I. 4t4-chloro-benzene-azo)phenol 0,0-diethylphosphoric ester 100 100 100 L. 4(4-ethoxy-benzene-azo)phenol 0,0-diethylphosphoric ester 100 100 M. 4(4-nitro-benzene-azo)phenol O-O-diethylphosphoric ester 100 100 100 35 N. 4(4-nitro-beuzene en phosphoric ester 100 100 100 O. 4(3-nitro-benzene-azo)phenol O phoric ester 100 100 100 P. 4(2-nitro-benzene-azo)phenol O-O-diethylphosphoric ester 100 63 0 4O EXAMPLE 11 Upon tarsal absorption, by introducing female flies, S-days old, into beakers previously treated with controlled amounts of benzene solutions of the test products of the preceding example and keeping the flies in contact for 20 hours, the following mortalities have been obtained:

0.125 g./m. 0.025 g./m. 0.005 gJni. Substance of active of active of active substance substance substance A- 100 94 27 B 100 100 0- 100 100 81 D- 100 88 5 100 100 83 5 F. 100 100 95 5 G 100 90 5 H--- 100 70 12 1--.- 100 100 70 100 90 2 100 100 100 i $8 22 EXAMPLE 12 Determination of the acute toxicity of the test products after oral or intravenous application:

The acute toxicity upon oral application has been determined by gastric probing and administration of the test products, dissolved in dirnethylacetamide, to rats weighing 18 to 20 g. The solvent interferes only very slightly with the toxic manifestations:

For the determination of intravenous toxicity the dim-ethylacetamide solution has been also employed.

The results obtained with some of the products claimed in the present patent application are reported in the following table:

application Substance oral LD/50 I intravenous LD/50 A 1.5 g./kg. do not cause any mortality. B 1.5 g./kg 400 mgJkg. cause a mortality of 20-30%. E 1 gflirog. causes a mortality 0 F 800 lug/kg. do not cause any 200 mgJkg. do not cause any mortality. mortality. I 800 rug/kg. cause a mortal- Do.

ity of 405075. M 800 mgJkg. do not cause any 150 mg.[kg. cause a mortality mortality. of 10-20 N f) mgJkg. cause a mortal- 200 mg./kg. cause a mortality ity of 10%. of 30%. O 112 mg./kg 69 rug/kg.

The above fly-leilling compounds can be employed in admixture with each other, and with other fly-killing substances, such as the known chlorinated organic compounds, other phosphoric and thiophosphoric esters, thiocyanates, pyrethrum esters, and synthetic pyrethrins, as well as with fungicides and fertilizers.

We claim:

l. The process of preparing phosphoric and thiophosphoric esters of the general formula R0 Ito 2"; T R" wherein R represents a lower alkyl, X represents a member of the group consisting of oxygen and sulfur, R represents a member of the group consisting of hydrogen, methoxy, para-ethoxy, para-chloro, ortho-chloro, orthonitro, meta-Intro, and para-nitro, and n represents the factors 0 and 1, said process comprising reacting, at a temperature ranging from O to C., a chloride of the group consisting of 0,0-dialkyl phosphoric and thiophosphoric acids of the general formula A l R0 X wherein Y represents chlorine, with a phenolic compound of the general formula wherein M represents an alkali metal, in a solvent for at least one of the two reactants and separating the reaction product.

2. The process of preparing phosphoric and thiophos phoric esters of the general formula Ito ii. T

wherein R represents a lower alkyl, X represents a merm ber of the group consisting of oxygen and sulfur, R represents a member of the group consisting of hydrogen, methoxy, para-ethoxy, para-chloro, ortho-chloro, orthonitro, meta-nitro, and para-nitro, and n represents the factors 0 and 1, said process comprising reacting, at a temperature ranging from O to 150 0., a chloride of the group consisting of 0,0-dialkyl phosphoric and thiophosphoric acids of the general formula /il no X wherein Y represents chlorine, with a phenolic compound; of the general formula formula RO J C T R wherein -R-representsa lower alkyl, X'represents a membenof thelgroupiconsisting of oxygen and sulfur, R rep- ;resentsa memberof the group consisting of hydrogen, -methoxy, para-ethoxy, para-chloro, ortho-chloro, orthonitro, meta-.nitro, and para-nitro, and n represents the Efactor'sfiand 1.

4. 4(3'-nitro-benZene-azo)phenol 0,0-diethylthiophosphoric ester.

'5. 4( 4' chloro benzene azo) phenol 0,0 diethylphosphoric ester.

6. 4(4-nitro-benzene-azo)phenol 0,0-diethylphosphoric ester.

7. 4(3'-nitro-benzeneazo)phenol 0,0'-diethylphosphoric ester.

8. 4(4' nitro-b-enzene azoxy)phenol 0,0 diethylphosphoric ester.

9. Inthe-art of control of flies at a locality, the improvement comprising applying to the locality a compound "taken fromthe group consisting of benzene-azo-phenol fi o-diethylthiophosphoric ester, 4 (4-chloro-benzene-azo) phenol Q,O;diethylthiophos phoric ester, 4(4'-n itro-benzene-azo 1phenol 0,0-diethylthiophosphoric ester, 4(3"- nitro-benzene-azmphenol 0,0-diethylthiophosphoric ester, 4('2-nitro-benzene-azo)phenol QO-diethylthiophosphoric ester, benzene-azoxy-phenol 0,0-diethylphosphoric ester, 4(4'-chlo110-benzene aZo)-phenol -v0,0-diethylphosphoric ester, 4(4-ethoxy benzene-az0)phenol Q,O'diethylphosphoric ester, 4(4-nitro-benzene-azo)phenol -O-,O-diethylphosphoric ester, 4(4'-nitro-benzene-azoxy)phenol 0,0 diethylphosphoric ester,.4( 3 -nitro benzene azo) phenol -0,0-diethylphosphon'c ester, 4(2-nitro-benzene azo) phenol 0,0-diethylphosphoric ester.

10. In the art of control of flies at a locality, the improvement comprising applying to the localityaa compound ofthe-formula in which R is a lower alkyl, X is a member of the group consisting of oxygen and sulphur, the R radical is taken from the group consisting of hydrogen, methoxy, paraethoxy, para-chloro, ortho-chloro, ortho-nitro, meta-nitro, and para-nitro, and Z is a radical taken from the group consisting of the linkage --N=N- and azoxy.

References Cited in the file of :this patent UNITED STATES PATENTS 2,741,656 Schmid et-al Apr. 10, 1956 2,803,580 .Metivier Aug. 20, 1957 2,807,637 Slagh et a1 Sept. 24, 1957 OTHER REFERENCES Kosolapoff: forganophosphorous Compounds, 1950, p. 266. 1 

10. IN THE ART OF CONTROL OF FLIES AT A LOCALITY, THE IMPROVEMENT COMPRISING APPLYING TO THE LOCALITY A COMPOUND OF THE FORMULA 